In my opinion, I find PR more important rather than Alexa ranking.

Backlinks
 

Page Rank and Alexa Rank are important in site value means when submitting any link we first check the pr and Alexa rank of site. Page Rank increases when you build good quality back-link in high pr, do-follow website and Alexa rank is dependent on site traffic. so low Alexa rank is better for site.

You are already in good positions , you just need to write a unique content for your site and make a good use of the social media sites for gaining the popularity for your site.

You should have to pay attention for driving more traffic on your site , because the more traffic will improve your alexa ranking and try to make a good content for your site which appeals the customers to stay on your site for a long time and if you are succeded for making customer stay on your site than automatically your PR increase .

This is very informative information, Thanks for sharing.

Both are different and both are important ...

Both are important ,,if you want a quality site in GOOGLE than PR is important and if you want a good amount of traffic for your site than Alexa Rank is important.

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if you want improve PR of your website .then you can increase traffics of your website.and do quality high pr site link building.then automatics you can as soon as your site PR increase.